Description
OAuth2 is a Ruby wrapper for the OAuth 2.0 and 2.1 authorization frameworks, including OpenID Connect (OIDC). From 0.4.0 to 2.0.21, a protocol-relative redirect Location returned to OAuth2::Client#request overrides the request authority, so the bearer Authorization header is sent to an attacker-controlled host, leaking the credential. This issue is fixed in version 2.0.22.
References5
- github.com/ruby-oauth/oauth2/commit/0f0a474f1b38453e119e660c2da…
- github.com/ruby-oauth/oauth2/releases/tag/v2.0.22
- github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2…
- lists.debian.org/debian-lts-announce/2026/10/msg00014.html
- github.com/ruby-oauth/oauth2/security/advisories/GHSA-pp92-crg2…
Metrics
- CVSS 3.1
-
8.6
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 39 · as of 13 November 2026
- CWE
- CWE-200CWE-601
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.